Field of the Invention
The present invention relates to wireless power, and more particularly, to a wireless power transmission apparatus and a coil structure for implementing the wireless power transmission apparatus.
Related Art
Generally, in order for a portable terminal such as a mobile phone, a notebook, and a PDA to be charged, the portable terminal needs to receive electric energy (or electric power) from an external charger. The portable terminal includes a battery cell for storing electric energy that supplied and a circuit for charging and discharging (supplying electric energy to the portable terminal) of the battery cell.
Electrical connection methods between a battery cell and a charger for charging the battery cell with electrical energy include a terminal supply method in which commercial power is supplied and converted into a voltage and a current corresponding to the battery cell and electrical energy is supplied to the battery cell through a terminal of the corresponding battery cell.
This terminal supply method is accompanied by the use of physical cables or wires. Accordingly, when much equipment of terminal supply method is used, many cables occupy a considerable work space, and are difficult to arrange, thereby deteriorating the appearance. Also, the terminal supply method may cause limitations such as an instantaneous discharge phenomenon due to potential differences between terminals, a burnout and fire due to sticking of foreign objects, a natural discharge, a lifespan and performance reduction of a battery pack and the like.
In recent years, charging systems (hereinafter, referred to as wireless power transfer systems) and control methods using the wireless power transmission method and control methods are being proposed in order to overcome the above-mentioned limitations. The wireless power transmission method is also referred to as a contactless power transmission method or a no point of contact power transmission method. The wireless power transfer system includes a wireless power transmission apparatus for supplying electric energy by a wireless power transmission method and a wireless power reception apparatus for receiving electric energy wirelessly supplied from the wireless power transmission apparatus to charge a battery cell. As technologies of wirelessly transmitting power, there are magnetic induction coupling and magnetic resonance coupling.